A location information sharing application (service) is now made available on a portable communication terminal, for example, a smartphone, and enables group-registered users to share location information of the respective users by displaying icons indicating present locations of the respective users by superimposing the icons on a map screen. In a system sharing location information as above, a portable communication terminal carried by each user in the group acquires location information by calculating a present location of its own by using a GPS (Global Positioning System) function, and displays an icon indicating the calculated present location of its own by superimposing the icon on the map screen while transmitting the acquired location information to a server. The server which has received the location information from the respective portable communication terminals collects the location information of the respective users in the group and transmits the collected location information of the respective users to respective portable communication terminals. The portable communication terminal which has received the location information from the server displays icons indicating the present locations of the respective users by superimposing the icons on the map screen. The users in the group can therefore determine more easily, for example, where and when to meet.
When a portable communication terminal is carried into a compartment of a vehicle, a recent system allows the portable communication terminal and a vehicular communication device, for example, a car navigation device to operate in cooperation by connecting the portable communication terminal and the vehicular communication device to enable data communications (see, for example Patent Literature 1).